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Merged
fabiopakk merged 1 commit into from
Dec 7, 2020
Merged

Optimize parser on large Viper files #477

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14 changes: 11 additions & 3 deletions src/main/scala/viper/silver/parser/FastParser.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -34,12 +34,21 @@ object FastParser extends PosParser[Char, String] {
*/
val standard_import_directory = "import"

var _lines: Array[Int] = null
var _line_offset: Array[Int] = null

def parse(s: String, f: Path, plugins: Option[SilverPluginManager] = None) = {
_file = f.toAbsolutePath

// Add an empty line at the end to make `computeFrom(s.length)` return `(lines.length, 1)`, as the old
// implementation of `computeFrom` used to do.
val lines = s.linesWithSeparators
_lines = lines.map(_.length).toArray
_line_offset = (lines.map(_.length) ++ Seq(0)).toArray

@fpoli fpoli Dec 7, 2020

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As described in the comment above, the ++ Seq(0) here is used to accurately reproduce an edge case of the old behavior. However, It's not clear to me how important that edge case is. Maybe we can ignore it.

var offset = 0
for (i <- _line_offset.indices) {
val line_length = _line_offset(i)
_line_offset(i) = offset
offset += line_length
}

// Strategy to handle imports
// Idea: Import every import reference and merge imported methods, functions, imports, .. into current program
Expand Down Expand Up @@ -155,7 +164,6 @@ object FastParser extends PosParser[Char, String] {
column = pos.column
}
ParseError(msg, SourcePosition(_file, line, column))
case _:Throwable =>
}
}

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18 changes: 10 additions & 8 deletions src/main/scala/viper/silver/parser/ParserPositions.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -30,15 +30,17 @@ case class FilePosition(file: Path, vline: Int, col: Int) extends util.parsing.i

trait PosComputer {
def computeFrom(index: Int) : (Int, Int) = {
var left = index
var i = 0
val arr = FastParser._lines
while (i < arr.length && left >= arr(i)){
left -= arr(i)
i += 1
val line_offset = FastParser._line_offset
val result = java.util.Arrays.binarySearch(line_offset, index)
if (result >= 0) {
// Exact match
val line = result
(line + 1, index - line_offset(line) + 1)
} else {
// The binary search returned `- insertionPoint - 1`
val line = - result - 2
(line + 1, index - line_offset(line) + 1)
}
val r1 = (i + 1, left + 1)
r1
}
}
/**
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